Truss manufacturing, and in particular, wood truss manufacturing initially involves cutting a series of raw lumber boards to make truss elements including, for example, top chords, bottom chords, and web members for use in assembling the truss. The raw lumber boards may commonly be dimensioned lumber boards such as 2×4's of various lengths. The cutting process may be automated and may involve efforts to minimize waste by selecting raw lumber board lengths that are very close to the actual length needed to make one or more elements.
After an element is cut, it may be arranged in its respective position in the truss on an assembly table, for example. In some cases, laser light diagrams may be projected onto the table showing the arrangement of truss elements to form the truss. Several truss elements may be arranged on the table and truss plates may be positioned at the intersection of the several elements. At each intersection, a truss plate may be placed under the assembly and on top of the assembly. When all of the elements of the truss are in position and the plates are placed, a press may be used to press the truss plates into the truss elements thereby securing the several elements at their respective intersections to form the truss.
During the above process, it should be appreciated that after a board is cut, it still looks basically like a plain 2×4 except that it may have a miter cut on one or both ends. As such, without more, it can be difficult to know how a particular element fits into the truss as a whole. Still further, once the position of the element is determined, the truss plates that secure it to adjoining elements need to be properly positioned. There are relatively strict tolerances on truss plate positioning because the truss plates are the only thing at each intersection that maintains the relative position of the truss elements during shipping and under load once the truss is installed in a structure. As such, typical truss plate locating involves measuring from particular points on the truss to edges of the plates to determine their position. For example, at the peak of a gabled truss, the top edge of the truss plate may be specified to be 3 inches down from the peak and the plate may be specified to be centered on the middle vertical member such that, for a 6 inch wide plate and a 3½ inch wide center vert, for example, the left and right edges of the plate may be specified as being 1¼ inches left and right of the edge of the center vertical member. Where multiple trusses are being assembled and, in particular, where many trusses are unique, the positioning of the members and the positioning of the plates can account for a large amount of time.